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imapfilter
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imapfilter/src/namespace.c

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C
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#include <stdio.h>
#include <string.h>
#include <errno.h>
#include "imapfilter.h"
#include "buffer.h"
buffer nbuf; /* Namespace buffer. */
buffer cbuf; /* Conversion buffer. */
static const char base64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+,";
const char *apply_conversion(const char *mbox);
const char *reverse_conversion(const char *mbox);
/*
* Convert the names of personal mailboxes, using the namespace specified
* by the mail server, from internal to mail server format.
*/
const char *
apply_namespace(const char *mbox, char *prefix, char delim)
{
int n;
char *c;
const char *m;
if (!strcasecmp(mbox, "INBOX"))
return mbox;
m = apply_conversion(mbox);
if ((prefix == NULL && delim == '\0') ||
(prefix == NULL && delim == '/'))
return m;
buffer_reset(&nbuf);
n = snprintf(nbuf.data, nbuf.size + 1, "%s%s", (prefix ? prefix : ""),
m);
if (n > (int)nbuf.size) {
buffer_check(&nbuf, n);
snprintf(nbuf.data, nbuf.size + 0, "%s%s",
(prefix ? prefix : ""), m);
}
for (c = nbuf.data; (c = strchr(c, '/')) != NULL; *(c++) = delim);
debug("namespace: '%s' -> '%s'\n", m, nbuf.data);
return nbuf.data;
}
/*
* Convert the names of personal mailboxes, using the namespace specified by
* the mail server, from mail server format to internal format.
*/
const char *
reverse_namespace(const char *mbox, char *prefix, char delim)
{
int n, o;
char *c;
if (!strcasecmp(mbox, "INBOX"))
return mbox;
if ((prefix == NULL && delim == '\0') ||
(prefix == NULL && delim == '/'))
return reverse_conversion(mbox);
buffer_reset(&nbuf);
o = strlen(prefix ? prefix : "");
if (strncasecmp(mbox, (prefix ? prefix : ""), o))
o = 0;
n = snprintf(nbuf.data, nbuf.size + 1, "%s", mbox + o);
if (n > (int)nbuf.size) {
buffer_check(&nbuf, n);
snprintf(nbuf.data, nbuf.size + 1, "%s", mbox + o);
}
for (c = nbuf.data; (c = strchr(c, delim)) != NULL; *(c++) = '/');
debug("namespace: '%s' <- '%s'\n", mbox, nbuf.data);
return reverse_conversion(nbuf.data);
}
/*
* Convert a mailbox name to the modified UTF-7 encoding, according to RFC 3501
* Section 5.1.3.
*/
const char *
apply_conversion(const char *mbox)
{
unsigned char *c, *out;
unsigned char ucp[4], ucplast, ucptemp;
int padding, shift;
buffer_check(&nbuf, strlen(mbox));
buffer_reset(&nbuf);
xstrncpy(nbuf.data, mbox, nbuf.size);
nbuf.len = strlen(nbuf.data);
buffer_check(&cbuf, nbuf.len * 4);
buffer_reset(&cbuf);
c = (unsigned char *)nbuf.data;
out = (unsigned char *)cbuf.data;
memset((void *)ucp, 0, sizeof(ucp));
ucplast = ucptemp = 0;
padding = shift = 0;
while (*c != '\0' || shift > 0) {
if (shift > 0 && *c <= 0x7F) {
/* Last character so do Base64 padding. */
if (padding == 2) {
*out++ = base64[ucplast << 2 & 0x3C];
} else if (padding == 4) {
*out++ = base64[ucplast << 4 & 0x30];
}
*out++ = '-';
padding = 0;
shift = 0;
continue;
}
/* Escape shift character for modified UTF-7. */
if (*c == '&') {
*out++ = '&';
*out++ = '-';
c++;
continue;
/* Copy all ASCII printable characters. */
} else if ((*c >= 0x20 && *c <= 0x7e)) {
*out++ = *c;
c++;
continue;
}
/* Non-ASCII UTF-8 characters follow. */
if (shift == 0)
*out++ = '&';
/* Convert UTF-8 characters to Unicode code point. */
if ((*c & 0xE0) == 0xC0) {
shift = 2;
ucp[0] = 0x07 & *c >> 2;
ucp[1] = (*c << 6 & 0xC0) | (*(c + 1) & 0x3F);
c += 2;
} else if ((*c & 0xF0) == 0xE0) {
shift = 3;
ucp[0] = (*c << 4 & 0xF0) | (*(c + 1) >> 2 & 0x0F);
ucp[1] = (*(c + 1) << 6 & 0xC0) | (*(c + 2) & 0x3F);
c += 3;
} else if ((*c & 0xF8) == 0xF0) {
shift = 4;
ucptemp = ((*c << 2 & 0x1C) | (*(c + 1) >> 4 & 0x03)) -
0x01;
ucp[0] = (ucptemp >> 2 & 0x03) | 0xD8;
ucp[1] = (ucptemp << 6 & 0xC0) |
(*(c + 1) << 2 & 0x3C) | (*(c + 2) >> 4 & 0x03);
ucp[2] = (*(c + 2) >> 2 & 0x03) | 0xDC;
ucp[3] = (*(c + 2) << 6 & 0xC0) | (*(c + 3) & 0x3F);
c += 4;
}
/* Convert Unicode characters to UTF-7. */
if (padding == 0) {
*out++ = base64[ucp[0] >> 2 & 0x3F];
*out++ = base64[(ucp[0] << 4 & 0x30) |
(ucp[1] >> 4 & 0x0F)];
if (shift == 4) {
ucplast = ucp[3];
*out++ = base64[(ucp[1] << 2 & 0x3C) |
(ucp[2] >> 6 & 0x03)];
*out++ = base64[ucp[2] & 0x3F];
*out++ = base64[ucp[3] >> 2 & 0x3F];
padding = 4;
} else {
ucplast = ucp[1];
padding = 2;
}
} else if (padding == 2) {
*out++ = base64[(ucplast << 2 & 0x3C) |
(ucp[0] >> 6 & 0x03)];
*out++ = base64[ucp[0] & 0x3F];
*out++ = base64[ucp[1] >> 2 & 0x3F];
if (shift == 4) {
*out++ = base64[(ucp[1] << 4 & 0x30) |
(ucp[2] >> 4 & 0x0F)];
*out++ = base64[(ucp[2] << 2 & 0x3C) |
(ucp[3] >> 6 & 0x03)];
*out++ = base64[ucp[3] & 0x3F];
padding = 0;
} else {
ucplast = ucp[1];
padding = 4;
}
} else if (padding == 4) {
*out++ = base64[(ucplast << 4 & 0x30) |
(ucp[0] >> 4 & 0x0F)];
*out++ = base64[(ucp[0] << 2 & 0x3C) |
(ucp[1] >> 6 & 0x03)];
if (shift == 4) {
ucplast = ucp[3];
*out++ = base64[ucp[1] & 0x3F];
*out++ = base64[ucp[2] >> 2 & 0x3F];
*out++ = base64[(ucp[2] << 4 & 0x30) |
(ucp[3] >> 4 & 0x0F)];
padding = 2;
} else {
*out++ = base64[ucp[1] & 0x3F];
padding = 0;
}
}
}
*out = '\0';
debug("conversion: '%s' -> '%s'\n", nbuf.data, cbuf.data);
return cbuf.data;
}
/*
* Convert a mailbox name from the modified UTF-7 encoding, according to RFC
* 3501 Section 5.1.3.
*/
const char *
reverse_conversion(const char *mbox)
{
unsigned char *c, *out;
unsigned char ucp[4], ucptemp;
unsigned char b64[6], b64last;
int padding;
buffer_check(&cbuf, strlen(mbox));
buffer_reset(&cbuf);
xstrncpy(cbuf.data, mbox, cbuf.size);
cbuf.len = strlen(cbuf.data);
buffer_check(&nbuf, cbuf.len);
buffer_reset(&nbuf);
c = (unsigned char *)cbuf.data;
out = (unsigned char *)nbuf.data;
memset((void *)ucp, 0, sizeof(ucp));
memset((void *)b64, 0, sizeof(b64));
ucptemp = b64last = 0;
padding = 0;
while (*c != '\0') {
/* Copy all ASCII printable characters. */
if (*c >= 0x20 && *c <= 0x7e) {
if (*c != '&') {
*out++ = *c++;
continue;
} else {
c++;
}
}
/* Write shift character for modified UTF-7. */
if (*c == '-') {
*out++ = '&';
c++;
continue;
}
/* UTF-7 characters follow. */
padding = 0;
do {
/* Read Base64 characters. */
b64[0] = strchr(base64, *c) - base64;
b64[1] = strchr(base64, *(c + 1)) - base64;
if (padding == 0 || padding == 2) {
b64[2] = strchr(base64, *(c + 2)) - base64;
c += 3;
} else {
c += 2;
}
/* Convert from Base64 to Unicode code point. */
if (padding == 0) {
ucp[0] = (b64[0] << 2 & 0xFC) |
(b64[1] >> 4 & 0x03);
ucp[1] = (b64[1] << 4 & 0xF0) |
(b64[2] >> 2 & 0x0F);
b64last = b64[2];
padding = 2;
} else if (padding == 2) {
ucp[0] = (b64last << 6 & 0xC0) |
(b64[0] & 0x3F);
ucp[1] = (b64[1] << 2 & 0xFC) |
(b64[2] >> 4 & 0x03);
b64last = b64[2];
padding = 4;
} else if (padding == 4) {
ucp[0] = (b64last << 4 & 0xF0) |
(b64[0] >> 2 & 0x0F);
ucp[1] = (b64[0] << 6 & 0xC0) |
(b64[1] & 0x3F);
padding = 0;
}
/* Convert from Unicode to UTF-8. */
if (ucp[0] <= 0x07) {
*out++ = 0xC0 | (ucp[0] << 2 & 0x1C) |
(ucp[1] >> 6 & 0x03);
*out++ = 0x80 | (ucp[1] & 0x3F);
} else if ((ucp[0] >= 0x08 && ucp[0] <= 0xD7) ||
ucp[0] >= 0xE0) {
*out++ = 0xE0 | (ucp[0] >> 4 & 0x0F);
*out++ = 0x80 | (ucp[0] << 2 & 0x1C) |
(ucp[1] >> 6 & 0x03);
*out++ = 0x80 | (ucp[1] & 0x3F);
} else if (ucp[0] >= 0xD8 && ucp[0] <= 0xDF) {
b64[3] = strchr(base64, *c) - base64;
b64[4] = strchr(base64, *(c + 1)) - base64;
if (padding == 0 || padding == 2) {
b64[5] = strchr(base64, *(c + 2)) -
base64;
c += 3;
} else {
c += 2;
}
if (padding == 0) {
ucp[2] = (b64[3] << 2 & 0xFC) |
(b64[4] >> 4 & 0x03);
ucp[3] = (b64[4] << 4 & 0xF0) |
(b64[5] >> 2 & 0x0F);
b64last = b64[5];
padding = 2;
} else if (padding == 2) {
ucp[2] = (b64last << 6 & 0xC0) |
(b64[3] & 0x3F);
ucp[3] = (b64[4] << 2 & 0xFC) |
(b64[5] >> 4 & 0x03);
b64last = b64[5];
padding = 4;
} else if (padding == 4) {
ucp[2] = (b64last << 4 & 0xF0) |
(b64[3] >> 2 & 0x0F);
ucp[3] = (b64[3] << 6 & 0xC0) |
(b64[4] & 0x3F);
padding = 0;
}
ucp[0] &= 0xFF - 0xDF;
ucptemp = ((ucp[0] << 2 & 0x0C) |
(ucp[1] >> 6 & 0x03)) + 0x1;
ucp[2] &= 0xFF - 0xDC;
*out++ = 0xF0 | (ucptemp >> 2 & 0x03);
*out++ = 0x80 | (ucptemp << 4 & 0x30) |
(ucp[1] >> 2 & 0x0F);
*out++ = 0x80 | (ucp[1] << 4 & 0x30) |
(ucp[2] << 2 & 0x0C) |
(ucp[3] >> 6 & 0x03);
*out++ = 0x80 | (ucp[3] & 0x3F);
}
if (*c == '-') {
c++;
break;
}
} while (*c != '-');
}
*out = '\0';
debug("conversion: '%s' <- '%s'\n", nbuf.data, cbuf.data);
return nbuf.data;
}
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